The invention relates to an arrestable tensioning device having an actuating device, a tensioning element coupled to the actuating device for executing a tensioning movement, and a releasable arresting device for the tensioning element, which arresting device comprises a first contour coupled to the tensioning element and an arresting element, which for arresting the tensioning element interacts with the first contour.
Such a tensioning device is known from DE 197 51 659. The tensioning device described there is part of a parking brake system and is used to tension brake pull cables of the parking brakes. The known tensioning device has an actuating device, which is actuable by means of an electric motor or muscular power. The actuating device enables a swivelling or rotating of a tensioning element, which is designed as a roller segment and coupled to the brake pull cables. The external contour of the roller segment is a ratchet mechanism and interacts with a spring-loaded detent pawl, which is pivotally mounted on the vehicle body.
For actuation of the parking brake system, the actuating device swivels the roller segment with simultaneous rolling-up of the pull cable. The roller segment in said case rotates in clockwise direction without being hindered by the adjacent, but non-locking detent pawl. In the arrested state, on the other hand, the roller segment is supported in an anticlockwise direction on the vehicle body by means of the ratchet mechanism and the detent pawl.
In order to release the parking brake, a second actuating device in the form of a hand lever is operated, which is coupled by means of a release cable to the detent pawl. The effect of operating the hand lever is that the detent pawl clears the ratchet mechanism of the roller segment. The freed roller segment rotates in anticlockwise direction under the tension of the brake pull cables.